Bidirectional power conversion circuit and bidirectional power converter

1. A bidirectional conversion circuit, comprising: a first bidirectional conductive network, a second bidirectional conductive network, a first switching transistor, a second switching transistor, a first diode, and a second diode, wherein the first bidirectional conductive network and the first switching transistor are connected in series to form a first branch, wherein a first end of the first branch is connected to a cathode of the first diode to form a first endpoint; the second bidirectional conductive network and the second switching transistor are connected in series to form a second branch, wherein a second end of the second branch is connected to an anode of the second diode to form a third endpoint; a second end of the first branch, an anode of the first diode, a first end of the second branch, and a cathode of the second diode are connected to form a second endpoint; the first switching transistor is turned on from a first time to a second time, and is turned off from the second time to a fifth time; and the second switching transistor is turned off from the first time to a third time, is turned on from the third time to a fourth time, and is turned off from the fourth time to the fifth time, wherein the first time is a start time of a positive half cycle of a current flowing into or flowing out of the second endpoint, the third time is an end time of the positive half cycle of the current, the second time is any time within a time interval from the first time to the third time, the fifth time is an end time of a negative half cycle of the current, and the fourth time is any time within a time interval from the third time to the fifth time.

2. The bidirectional conversion circuit according to claim 1 , wherein the first bidirectional conductive network is a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), or two parallel diodes having opposite polarities.

3. The bidirectional conversion circuit according to claim 1 , wherein the second bidirectional conductive network is an MOSFET, an IGBT, or two parallel diodes having opposite polarities.

4. The bidirectional conversion circuit according to claim 1 , wherein a conductive voltage drop of the first bidirectional conductive network is less than a conductive voltage drop of the first diode, and a sum of the conductive voltage drop of the first bidirectional conductive network and a conductive voltage drop of a parasitic diode of the first switching transistor is greater than the conductive voltage drop of the first diode; and a conductive voltage drop of the second bidirectional conductive network is less than a conductive voltage drop of the second diode, and a sum of the conductive voltage drop of the second bidirectional conductive network and a conductive voltage drop of a parasitic diode of the second switching transistor is greater than the conductive voltage drop of the second diode.

5. The bidirectional conversion circuit according to claim 1 , wherein the first switching transistor is a metal-oxide-semiconductor field-effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT); and the second switching transistor is an MOSFET or an IGBT.

6. The bidirectional conversion circuit according to claim 1 , wherein the first diode is a fast recovery diode or a silicon carbide (SiC) diode; and the second diode is a fast recovery diode or a silicon carbide SiC diode.

7. The bidirectional conversion circuit according to claim 1 , wherein the bidirectional conversion circuit is used for a synchronous rectification circuit or an inverter circuit.

8. The bidirectional conversion circuit according to claim 1 , wherein the bidirectional conversion circuit further comprises a controller, wherein the controller is configured to: control the first switching transistor to be turned on or off; control the second switching transistor to be turned on or off; or control the first switching transistor and the second switching transistor to be turned on or off.

9. A bidirectional converter, comprising: a first bidirectional conversion circuit including a first bidirectional conductive network forming a first branch and a second bidirectional conductive network forming a second branch for conversion of direct current (DC)/alternating current (AC) or AC/DC voltages through the first and second branches; a second bidirectional conversion circuit; a third bidirectional conversion circuit; a transformer, wherein the transformer comprises a primary-side winding and a secondary-side winding, one end of the secondary-side winding of the transformer is connected to a second endpoint of the first bidirectional conversion circuit, and the other end of the secondary-side winding of the transformer is connected to a second endpoint of the second bidirectional conversion circuit; a resonant cavity, wherein the resonant cavity comprises a first port, a second port, a third port, and a fourth port, the first port is connected to a second endpoint of the third bidirectional conversion circuit, the second port is connected to a third endpoint of the third bidirectional conversion circuit, and the third port and the fourth port are separately connected to the primary-side winding of the transformer; and a bridgeless power factor correction (PFC) circuit, wherein the bridgeless PFC circuit comprises two alternating current (AC) ports and two direct current (DC) ports, and the two DC ports are separately connected to a first endpoint and the third endpoint of the third bidirectional conversion circuit.

10. The bidirectional converter according to claim 9 , wherein the bidirectional converter further comprises: a capacitor, wherein a first endpoint of the first bidirectional conversion circuit is connected to a first endpoint of the second bidirectional conversion circuit and is connected to a positive end of the capacitor, and a third endpoint of the first bidirectional conversion circuit is connected to a third endpoint of the second bidirectional conversion circuit and is connected to a negative end of the capacitor.

11. A bidirectional converter, comprising: a first bidirectional conversion circuit including a first switch on a first branch and a second switch for a second branch for conversion of direct current (DC)/alternating current (AC) or AC/DC voltages through the first and second branches; a second bidirectional conversion circuit; a third bidirectional conversion circuit; a transformer, wherein the transformer comprises a primary-side winding and a secondary-side winding, one end of the secondary-side winding of the transformer is connected to a second endpoint of the first bidirectional conversion circuit, and the other end of the secondary-side winding of the transformer is connected to a second endpoint of the second bidirectional conversion circuit; a resonant cavity, wherein the resonant cavity comprises a first port, a second port, a third port, and a fourth port, the first port is connected to a second endpoint of the third bidirectional conversion circuit, the second port is connected to a third endpoint of the third bidirectional conversion circuit, and the third port and the fourth port are separately connected to the primary-side winding of the transformer; and a bridgeless power factor correction (PFC) circuit, wherein the bridgeless PFC circuit comprises two alternating current (AC) ports and two direct current (DC) ports, and the two DC ports are separately connected to a first endpoint and the third endpoint of the third bidirectional conversion circuit.

12. The bidirectional converter according to claim 11 , wherein the bidirectional converter further comprises: a capacitor, wherein a first endpoint of the first bidirectional conversion circuit is connected to a first endpoint of the second bidirectional conversion circuit and is connected to a positive end of the capacitor, and a third endpoint of the first bidirectional conversion circuit is connected to a third endpoint of the second bidirectional conversion circuit and is connected to a negative end of the capacitor.